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L-Arginine Supplements Reviewed by


  • What is L-arginine? L-arginine (or arginine) is an amino acid that is necessary for the body's production of nitric oxide, a compound that relaxes blood vessels and allows more blood to flow through arteries. The form in supplements is typically "free form" arginine, but is sometimes a compound, such as L-arginine HCl. (See What It Is). Not all labels clearly list the amount of arginine. (See What to Consider When Buying), but you can use the Results table to easily compare amounts of arginine in tested supplements.
  • What are the health benefits of L-arginine? L-arginine may modestly improve symptoms of congestive heart failure, exercise intolerance in people with angina, and leg pain due to intermittent claudication, as well as exercise endurance in recreational and older athletes. However, it does not appear to improve blood flow to muscle or athletic performance in athletically active young adults. Some, but not all, studies have shown some modest benefits in sexual dysfunction and Raynaud's syndrome. L-arginine can provide nutritional support and stimulate the immune system in some people with cancer. It may also improve chemotherapy response rate and slow the growth of certain breast and colon tumors, but be aware it may actually promote the growth of others (See What It Does).
  • How much L-arginine to take? Dosage depends on the condition being treated, but is typically several thousand milligrams per day (See Dosage).
  • Best L-arginine products? Among the products that passed our laboratory tests (See What CL Found), we selected Top Picks for arginine for general use, cardiovascular, sexual enhancement, and sport.
  • L-arginine safety and side effects: L-arginine supplementation appears to be generally safe and well tolerated in healthy individuals, although stomach upset may occur, and capsules have been reported to irritate the esophagus — so be sure to take with water. L-arginine may interact with blood-pressure lowering and diabetes medications. Do not use if you have had a heart attack, and do not use to treat serious conditions including congestive heart failure, angina, or intermittent claudication without physician supervision. For details, see Concerns and Cautions.

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Alphabetical list of L-arginine supplement brands compared in this review

View Larger Image 6070_small_6070_small_CountryLife-LArginine-Small-2018.jpg

Country Life L-Arginine Caps

View Larger Image 5842_small_DailyWellness-L-Arginine-Small-2017.jpg

Daily Wellness ArginMax- Women

View Larger Image 5843_small_ElementsOfHealth-L-Arginine-Small-2017.jpg

Elements of Health Care L-Arginine Plus - Grape

View Larger Image 6172_small_6172_small_GNC-LArginine-Small-2018.jpg

GNC L-Arginine

View Larger Image 5827_small_Havasu-L-Arginine-Small-2017.jpg

Havasu Nutrition L-Arginine Extra Strength

View Larger Image 5844_small_MuscleTech-L-Arginine-Small-2017.jpg

MuscleTech L-Arginine SX-7 Black Onyx

View Larger Image 5828_small_NOW-L-Arginine-Small-2017.jpg

NOW L- Arginine

View Larger Image 5829_small_PipingRock-L-Argenine-Small-2017.jpg L-Arginine

View Larger Image 5841_small_PurethenticNaturals-Arginine-Small-2017.jpg

Purethentic Naturals Premium Arginine

Puritan's Pride L-Arginine

View Larger Image 5830_small_Rexall-L-Arginine-Small-2017.jpg

Rexall [Dollar General] L- Arginine

View Larger Image 5831_small_Solgar-L-Arginine-Small-2017.jpg

Solgar L-Arginine 500 mg

View Larger Image 5832_small_SpringValley-L-Arginine-Small-2017.jpg

Spring Valley [Walmart] L- Arginine

View Larger Image 5833_small_SundownNaturals-L-Arginine-Small-2017.jpg

Sundown Naturals L-Arginine 500 mg

View Larger Image 5834_small_Swanson-L-Arginine-Small-2017.jpg

Swanson Super Strength L-Arginine

View Larger Image 5837_small_TheVitaminShoppe-L-Arginine-Small-2017.jpg

The Vitamin Shoppe L-Arginine

View Larger Image 5835_small_Twinlab-L-Arginine-Small-2017.jpg

Twinlab L-Arginine

View Larger Image 5836_small_Vitacost-L-Arginine-Small-2017.jpg

Vitacost L- Arginine HCl

View Larger Image 5839_small_VitaminWorld-L-Arginine-Small-2017.jpg

Vitamin World Maximum Strength L-Arginine

You must be a member to get the full test results along with's findings, recommendations, and quality ratings. You'll get results for 18 L-arginine supplements: ten selected by and eight that passed the same testing in our voluntary Quality Certification Program. There's also information about one product that is similar to one which passed testing but is sold under a different brand name.

You'll get the following information about L-arginine supplements in this comprehensive review:
  • Which L-arginine supplements passed or failed testing
  • Which L-arginine supplements are the best value and CL's Top Picks
  • What L-arginine can and cannot do for your health
  • How forms of L-arginine ("free form," L-arginine HCl, and L-arginine-alpha-ketoglutarate) differ from one another
  • The dose of L-arginine for specific uses
  • What to look for on product labels and how to take L-arginine supplements
  • Why the amino acid citrulline is often added to L-arginine supplements and whether it's been shown to help
  • Cautions, side effects, and drug interactions with L-arginine

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Additional Information
Tested through CL's Quality Certification Program prior to, or after initial posting of this Product Review.